component
2N3904
Public Made by Adomby adom
onsemi general-purpose NPN BJT, TO-92. 40 V, 200 mA, hFE 100-300, fT 300 MHz. Datasheet-verified.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdown2N3904
onsemi · NPN BJT (general purpose) · TO-92
The 2N3904 is the default general-purpose NPN bipolar transistor, in a TO-92 through-hole package. It switches and amplifies small signals up to about 200 mA and 40 V, with a current gain (hFE) of roughly 100 to 300 and a transition frequency near 300 MHz, so it works as a switch, a small-signal amplifier, or a logic-level buffer. The TO-92 leads are E, B, C in order (pin 1 = emitter). Its PNP complement is the 2N3906.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | E | passive | Emitter of the NPN transistor. VEBO breakdown 6.0 V. In TO-92 (viewed from the flat/front, leads down), lead 1 is Emitter. |
| 2 | B | input | Base of the NPN transistor. Controls collector current with hFE typ 100-300 at IC=10 mA, VCE=1.0 V. VBE(sat) ≤ 0.85 V at IC=10 mA, IB=1.0 mA. |
| 3 | C | passive | Collector of the NPN transistor. VCEO breakdown 40 V, VCBO breakdown 60 V, IC continuous max 200 mA. VCE(sat) ≤ 0.2 V at IC=10 mA, IB=1.0 mA. |
Key specifications
| Parameter | Value |
|---|---|
| Type | NPN bipolar transistor |
| Collector-emitter (VCEO) | 40 V |
| Collector current (IC) | 200 mA |
| DC gain (hFE) | 100-300 |
| Transition freq (fT) | 300 MHz |
| Power dissipation | 625 mW |
| Pinout | E-B-C (pin 1 = emitter) |
| Package | TO-92 |
Ordering variants
2N3904BU (TO-92)2N3904TA (TO-92, ammo pack)
CAD (KiCad official)
- Symbol:
Transistor_BJT:2N3904 - Footprint:
Package_TO_SOT_THT:TO-92_Inline - 3D model: TO-92 (KiCad packages3D)
- 3D model files:
2n3904-etched.step/2n3904-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);2n3904.step/2n3904.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: onsemi datasheet (7 pp, sha256
39b20929e3d2d854, retrieved 2026-08-17, tier: manufacturer) - Extractor:
ds2sf(Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate. - CAD: KiCad official libraries (CC-BY-SA 4.0).